Pressure indicator



Ma 31, 1938. y M. KADENACY 2, 9,

' PRESSURE INDICATOR Filed June 1, 1936 ,,.,,,m,,.31,s38 1 k v 2,119,166

UNITED STATES PATENT orrics mssm mmoa'ron Michel Kadenacy, Paris, France, assignor of onehall to Armstrong Whitworth Securities Company, Limited, London, England Application June-1, 1936, serial No. 82,958 In. Great Britain January 11, 1936 I 4 Claims. (01. 73-51 The present invention relates to pressure in.- the cylinder, and for the purpose of revealing dicating devices and more particularly to devices any corrections that require to be made in the of the kind which are suitable for giving indicatiming and arrangement of the engine. tions of fluid pressures which vary rapidly be- One example of a convenient embodiment of 5 tween wide limits as a function of time and in the invention suitable for use in examining the 5 which the said variations are repeated at unipressure variations and the movement of the gases form intervals, as occurs for example in the in the exhaust or inlet duct of an internal comcylinder and in the inlet and exhaust ducts of 'bustion enginewill now be described by way of internal combustion engines. example only, without limitation to this par- Y The object of the invention is to provide a deticular use, and "with reference to the accom- '10 vice of the above kind, which is capable of giving panying drawing, in which: 1 reliable indicationsof pressures free from in- Figure 1 shows an axial section through theaccuracies which might be occasioned by the device.

rapidity at which the indication oi. pressure must Figure 2 is asection take'n'o'n the line H be obtained, j in Figure 1. v

The invention consists in a pressure indicating In the example illustrated in the drawing, the I device for an internal combustion engine includdevice comprises a sleeve formed of two can'- ing pressure sensitive indicating means for regcentric tubular elements I, 2 between which is istering variations in pressure above and below situated. a rotatable ported shutter 3, carrying a atmospheric pressure, and variations in the velocsprocket wheel 4 for permitting the shutter to -be 0 ity and direction of movement of fluids in the driven by any suitable means, for example from inlet and exhaust conduits of the engine, a memthe crank shaft oi the engine.

her having ports connected to the pressure sensi- This sleeve L2 is open-at both ends and is tive indicating means, a complementary member mounted with freedom for angular movement in having ports co-operatingwith the first menend supports 5 in the form of rings adapted to be tioned ports, ducts extending in opposite direc connected rigidly by means of flanges 6 within the tions with respect to the axis of the conduit and inlet or exhaust duct of an internal combustion connecting said second mentioned ports to the engine. source of pressure, a shutter element relatively -The outer sleeve element 2 has a pair of ports I rotatable with respect to said members and hav- I, 8 for connection through suitable unions 8, ll 30 1 ing ports co-operating ,with the ports in the with two pressure sensitive indicators such; as members to connect the source or pressure to the water or mercury manometers 23, 24 capable of indicating means and means to produce said indicating alllpressures from approximately zero relative rotation whereby the indicating means absolute to the highest pressure encountered, and are connected to the source of pressure at recurthe inner sleeve member I has two corresponding ring intervals of time.- ports ll, 12 connected with short tubular ducts- The pressure indicating device according to the l3, l4 extending into the interior of the sleeve invention .is very suitable for indicating the wide and having their outlet ends facing in opposite and rapid. changes from a high pressure to a directions along the axis of the sleeve.

practical vacuum that occur in the cylinder and The rotary shutter I also has a pair of ports 4 in the exhaust and inlet 'ducts of an internal I 5, l6 co-operating with the ports in the sleeve combustion engine during its operation, and is so as to establish and cut oil communication particularly useful in enabling the movements between the interior of the duct and the pressure of the exhaust and inlet gases to be examined, sensitive means intermittently during its rotaespecially when it is desired to determine when tion.-

the gases leave the cylinder as a mass, consequent One of the fixed end pieces 5 supporting the upon the opening of the exhaust orifice, at a sleeve carries'a scale l1, and the sleeve carries speed higher than that obtaining when an adiaa pointer it moving over the scale l1 and is batic flow only is involved and in such a short provided with an adjusting lever l9, whereby the interval of time that they are discharged wholly sleeve can be moved through any required angle 50 or substantially wholly rrom the cylinder, leaving as and when desired for the purpose of varying a high degree of vacuum behind them and when. the moment at which the ports in the sleeve and the return of these gases occurs, for the purpose shutter coincide during the rotation of the of establishing a timing of inlet suitable for uti-- shutter.

lizingthe intervening depression when charging The sleeve also comprises suitable water pass5 tuations has been obtained and then by varying sages 20 for connection to a supply of cooling water through the connections 2| and 22.

When such a device is employed for obtaining indications of, pressure in the inlet or exhaust duct of an internal combustion engine, and the shutter is driven in synchronism with the rotation of the crankshaft, each time the ports in the shutter and sleeve coincide a pressure impulse will be transmitted to the pressure indicating means and will. give a reading of pressure for a determined crank angle, and this reading will not be due to one single impulse but to a series of impulses succeeding each other with a rapidity depending upon the engine speed. Consequently the reading may be continued at this point until a stable indication substantially freeirom flucthe angular adjustment of the stationary sleeve, readings at any desired angular intervals of crank angles may be obtained in succession with a high degree of accuracy.

Further, according'to the direction of movement of the fluid in the conduit, different pressure readings will be obtained from the two ports on the sleeve and these differences in pressure will enable the speed and direction of movement of the fluid to be determined.

Records of the changes in pressure occurring in the exhaust duct of an internal combustion engine taken with a. device such as that described above show clearly the period of delay that occurs before the gases leave the cylinder, the abrupt rise in pressure due to the mass exit of the gases; the immediately following abrupt fall to a high degree of vacuum when the mass has passed beyond the pressure indicator, and the subsequent rise in pressure, due to the return of the gases.

A device such as that described is suitable for use on an internal combustion engine during the exhaust and admission phases, for registering static and dynamic pressures with a simultaneous indication of the directions and of the intensity -of the gaseous currents, in order to detect the fluctuations, the speeds, the pressures and the mass movements of the gases in the admission duct, the exhaust duct and the cylinder.

I claim: 1. A pressure indicating device for an internal combustion engine including pressure sensitive indicating means for registering variations in pres-.

ter element relatively rotatable with respect to said members and having ports co-operating with the ports in the members to connect the sourceof pressure to the indicating means and means to produce said relative rotation whereby the indicating means are connected to the source of pressure at recurring intervals of time.

2. A pressure indicating device for an internal combustion engine including pressure sensitive indicating means for registering variations in pressure above and below atmospheric pressure and variations in the velocity and direction of movement of fluids in the inlet and exhaust conduits of theengine, a sleeve element having ports connected to the pressure sensitive indicating means, a complementary sleeve element having ports co-operating with the first mentioned ports, ducts extending in opposite directions with respect to the axis of the conduit and connecting said second mentioned ports to the source of 7 pressure, ashutter element relatively rotatable with respect to said sleeve elements and having ports co-operating with the ports in said'elements to connect the source of pressure to the indicating means, and means to produce said relative rotation whereby the indicating means are connected to the source of pressure at recurring intervals of time.

3. A pressure indicating device as claimed in claim 2, including a fixed member supporting said sleeve elements with freedom for angular movement and an adjusting member on said sleeve elements to permit the sleeve elements to be moved through any desired angle for the purpose of varying the moment at which the ports in the sleeves and shutter coincide.

4. A pressure indicating devicefor an internal combustion engine including pressure sensitive indicating means for registering variations in pressure above and below atmospheric pressure and Variations in the velocity and direction of movement of fluids in the inlet and exhaust conduits of the engine, a sleeve element having ports connected to the pressure sensitive indicating means and having a hollow wall, a complementary sleeve element having ports co-operating with the first mentioned ports and having a hollow wall, ducts extending in opposite directions with'respect to the axis of the conduit and connecting said second mentioned ports to the source .of pressure, a shutter element relatively rotatable with respect to said sleeve elements and having 'ports co-operating with the ports in said elements to connect the source of pressure to the indicating means,-means to 'circulatecooling fluid whereby the indicatingmeans are connected to I the source of pressure. at recurring intervals of 

